By S. Savas Durduran and Ali Erdi, Department of Geodesy and Photogrammetry, Selcuk University, Konya, Turkey; and Fatih Kara and Yasemin Durduran, Province Medical Directorate, Konya, Turkey

In Turkey there are approximately 1,300,000 human carriers of beta thalassemia and 4,000 patients. Thalassemia (Mediterranean anemia) is a hereditary blood disease often found in Mediterranean countries. The disease is passed from the mother and father to their children and affects the children's genes. It is expensive to cure, but it can be prevented. According to analyses, the percentage of beta thalassemia carriers is 2.12 percent in the Turkish population. It is well known that genetic transitive diseases, such as thalassemia, are a serious problem in Turkish society, which has a high rate of marriages between close relatives. Therefore, counseling has been given in Konya Centrum and its provinces to newly married couples, married couples expecting a child, and persons who have or have had thalassemia disease in their families.

To determine the presence of thalassemia disease, a blood test—the high-performance liquid chromatography (HPLC) electrophoresis method—is given to couples who are going to marry. The results of the tests are recorded, as well as information provided by thalassemia patients on forms at the hospitals. The HPLC electrophoresis method is also used to examine the carriers, including those with anemia and anemia symptoms who are not responding to treatment. In order to track the disease and its carriers, all this information—including analyses, statistical tables, and graphics—is stored in a database from which a thalassemia map of Konya was derived.

This interactive and layered map benefits health professionals, who are the decision makers and analysts, regarding the progress of the disease. They can perform positional and nonpositional analyses and examinations, including storing, processing, and entering positional and nonpositional geographic information into the database.

Preparing a Thalassemia Map Using GIS

Developing a database is the most important step for the GIS. Prior to determining the positional and nonpositional data, the main objective for the thalassemia disease GIS program needed to be determined. Then data that serves this goal had to be obtained and the goal achieved using GIS software. For the Department of Geodesy and Photogrammetry of Selcuk University's Konya campus and the Province Medical Directorate, ArcView was deemed the most efficient software to help determine geographic locations of thalassemia disease. With the collected data stored in ArcView, and by examining and processing the data, decisions could be made regarding the disease.

Konya Centrum and its provinces were selected as the working zone for determining thalassemia disease. Following the transfer of positional data concerning the working zone to the system, information with regard to thalassemia disease was also transferred to the system from the records kept regularly by the Local Health Authority and Family Planning and Child Health branch.

Analyses of the disease are made by examining demographic information, such as population and the locations where the thalassemia patients are more than four years of age; getting nonspatial disease information from spatial information depending on the working zone; and getting spatial information from nonspatial information. This data includes the name of the patient, address, province, age, and village clinic that treated the patient.

Using ArcView, analyses show that Konya Centrum has the most thalassemia patients and the highest rate of the disease. The Saray�n�, Eregli, and Derbent-H�y�k districts have the next highest incidences of the disease.

Hereditary Blood Disease: Thalassemia

Thalassemia can be seen in children in the following forms:

• Major Thalassemia (Mediterranean anemia)—This form of the disease is progressive. Children who have major thalassemia are normal at birth. It becomes a serious blood disease when the children are about six months of age and need regular blood transfusions. These patients are also inclined to have infections.
• Thalassemia Intermedia—This is the milder form of the disease and requires fewer blood transfusions. Symptoms usually begin at an older age.
• Minor Thalassemia—Persons with this form of the disease are healthy, except for mild anemia. These patients are thalassemia carriers but do not require treatment. They can maintain their lives normally. Most carriers are unaware they are carrying the disease. It is important to know whether a person is a carrier or not, because thalassemia carriers can have children who may have major thalassemia. If both the father and mother are Mediterranean anemia carriers (major thalassemia), the probability of their children having major thalassemia is 25 percent and being carriers is 50 percent.

Conclusion

A GIS map of thalassemia disease was prepared using informational technology and ArcView. This positional map, which displays places where the disease occurs and the growth rate of the disease, helps medical professionals track patients. With GIS it makes the information more accurate and reliable.

Using the health records in a GIS makes it easier for health personnel to determine locations of high risk. GIS can help users understand the causes of thalassemia disease, track its spread, and determine at what rate it occurs. Then steps can be taken to prevent the disease.

GIS also benefits health treatment programs in rapidly developing and growing cities to provide the local people with the best economic and health conditions.

For further information, contact S. Savas Durduran, resident assistant, Selcuk University, Department of Geodesy and Photogrammetry, Konya Campus, Konya, Turkey (tel.: 90-332-2231936, fax: 90-332-2410065, e-mail: durduran@selcuk.edu.tr).